Return the results of init attachment request

Methods ``openstack.block_storage.v3.volume.Volume.init_attachment`` and
``block_storage.init_volume_attachment`` now return the results of the
POST request instead of None. This replicates the behaviour of
cinderclient; the returned data is used by nova and ironic for managing
volume attachments.

Change-Id: I55ad94c872e807668b85125b32f142c3a8cf40bf

openstack/block_storage/v3/_proxy.py

@@ -948,9 +948,9 @@ class Proxy(_base_proxy.BaseBlockStorageProxy):
             :class:`~openstack.block_storage.v3.volume.Volume` instance.
         :param dict connector: The connector object.
 
-        :returns: None"""
+        :returns: Dictionary containing the modified connector object"""
         volume = self._get_resource(_volume.Volume, volume)
-        volume.init_attachment(self, connector)
+        return volume.init_attachment(self, connector)
 
     def terminate_volume_attachment(self, volume, connector):
         """Update volume status to 'in-use'.

openstack/block_storage/v3/volume.py

@@ -290,7 +290,8 @@ class Volume(resource.Resource, metadata.MetadataMixin):
         """Initialize volume attachment"""
         body = {'os-initialize_connection': {'connector': connector}}
 
-        self._action(session, body)
+        resp = self._action(session, body).json()
+        return resp['connection_info']
 
     def terminate_attachment(self, session, connector):
         """Terminate volume attachment"""

openstack/tests/unit/block_storage/v3/test_volume.py

@@ -545,7 +545,14 @@ class TestVolumeActions(TestVolume):
     def test_init_attachment(self):
         sot = volume.Volume(**VOLUME)
 
-        self.assertIsNone(sot.init_attachment(self.sess, {'a': 'b'}))
+        self.resp = mock.Mock()
+        self.resp.body = {'connection_info': {'c': 'd'}}
+        self.resp.status_code = 200
+        self.resp.json = mock.Mock(return_value=self.resp.body)
+        self.sess.post = mock.Mock(return_value=self.resp)
+        self.assertEqual(
+            {'c': 'd'}, sot.init_attachment(self.sess, {'a': 'b'})
+        )
 
         url = 'volumes/%s/action' % FAKE_ID
         body = {'os-initialize_connection': {'connector': {'a': 'b'}}}

releasenotes/notes/block-storage-init-return-95b465b4755f03ca.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    Methods ``openstack.block_storage.v3.volume.Volume.init_attachment`` and
+    ``block_storage.init_volume_attachment`` now return the results of the POST
+    request instead of None. This replicates the behaviour of cinderclient; the
+    returned data is used by nova and ironic for managing volume attachments.